Comparison of melanosomes between normal human melanocytes and melanoma cells for early diagnosis of melanoma

Abstract

Melanosomes are specific organelles transporting melanins from melanocytes to keratino-cytes. Recent studies on melanosomes conducted using diverse surface analysis techniques reveal that the shapes of normal melanosomes are ellipsoidal and spherical. Then, it will be of great interest, if the shapes of melanosomes are different, because it can be used to distinguish mutated cells from normal cells. Herein, melanosomes from four different kinds of skin cells including normal epidermal cells and cancer cells were studied using atomic force microscopy (AFM), scanning electron microscopy (SEM), and Raman spectroscopy. AFM and SEM revealed that melanosomes from normal human melanocytes were ellipsoidal or spherical depending on kinds of melanins. In melanotic melanoma cells, ring-shaped as well as ellipsoidal and spherical melanosomes were found and in amelanotic melanoma cells, there were no formal and normal forms. Suggesting the shape of melanosomes from normal melanocytes, melanotic melanoma cells and amelanotic melanoma cells are different. Raman spectroscopy demonstrated that all samples showed melanin peaks, in spite of difference in intensity, except amelanotic melanoma cell samples, indicating that presence and absence of melanins may affect the morphology of melanosomes and cellular modification may have impact on melanosomes. In this study, although the detailed reasons for the differences in the morphology of melanosomes is not understood yet, the results provide new insights into the potential of application for early diagnosis of skin cancer.